"Marsupial" comes from "marsupialis/marsupium" (latin) = pouch/purse. Which is exactly what a kangaroo has on its stomach.
Kangaroos (macropodidae = big feet) are marsupials and belonging to a family consisting of 65 species with 11 branches. They vary in size from 23 cm up to 2 meters, and in weight from 0.5 kg up to 90 kg.